topic How program can find out that a file can be copied? in Operating System - OpenVMS

How program can find out that a file can be copied?

Jurek Sokolowski — Fri, 14 Oct 2005 04:37:51 GMT

I need to copy a file with LIB$SPAUN('copy… . What system service can I use to determine that file to be copied is not allocated by other program (e.g. that file transfer from different machine has finished). From DCL I can use SHOW DEV /FIL to check it, but I have no idea how to do that from FORTRAN or C level.

Re: How program can find out that a file can be copied?

Volker Halle — Fri, 14 Oct 2005 04:43:44 GMT

Jurek,

there is no system service to tell, whether a file is opened from another process.

You could try to open the file in exclusive mode, allowing no sharing, which would fail, if another process has the file open.

Volker.

Re: How program can find out that a file can be copied?

Kris Clippeleyr — Fri, 14 Oct 2005 04:45:19 GMT

Jurek,

You might want to try SYS$OPEN.
See HELP SYSTEM_SERVICES $OPEN , and the Record Management Services Reference manual.

Regards,
Kris (aka Qkcl)

Re: How program can find out that a file can be copied?

Karl Rohwedder — Fri, 14 Oct 2005 05:15:56 GMT

Have a look into the utility FILES_INFO.
It can display, if a file is locked and by whom.
Source code (C and macro) is provided.
May you can get some hints.

You find it at the usual place at Hunter Goatley filearchive:

http://www.process.com/openvms/index.html

regards Kalle

Re: How program can find out that a file can be copied?

Volker Halle — Fri, 14 Oct 2005 05:24:21 GMT

Jurek,

the following statement in FORTRAN could do, what you want:

OPEN (UNIT=1, FILE='test.dat',STATUS='OLD')

$! File test.dat not access by any process
$ run ITRC_965548

$! Access file
$ open/read x test.dat
$ run ITRC_965548
%FOR-F-OPEFAI, open failure
unit 1 file USERDISK1:TEST.DAT;
user PC 00000000
-RMS-E-FLK, file currently locked by another user
...

Volker.

Re: How program can find out that a file can be copied?

Jurek Sokolowski — Fri, 14 Oct 2005 05:40:07 GMT

Opening a file as a test is simple and works fine. Thank you very much for your help.
Jurek

Re: How program can find out that a file can be copied?

John Gillings — Sun, 16 Oct 2005 17:43:46 GMT

The best approach is to simply attempt to copy the file and react to any errors. Any test is subject to timing windows. Yes, the file may be available NOW, but that doesn't say it will still be available when you attempt the copy.

The simplest way to copy a file under program control is using callable CONVERT.

Attached is a MACRO32 program to perform a COPY. Check the return status to see if it was successful.